Objective: To investigate the effect of glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide on hypoxia/reoxygenation (H/R)-induced cardiomyocytes death under high glucose condition and the potential mechanisms.
Methods: H9C2 cardiomyocytes were divided into 4 groups: normal glucose (N, 5 mmol/L), high glucose (G, 20 mmol/L), high glucose in combination with liraglutide (L, 100 nmol/L), high glucose in combination with liraglutide and wortmannin (W, 25 nmol/L). The apoptosis of H9C2 was detected by TUNEL assay. Nitric oxide synthetase(eNOS), nitric oxide (NO) and reactive oxygen(ROS) in supernatants were measured by enzymatic analysis. p-PI3K, PI3K, p-Akt, Akt, Bcl-2, caspase-3 were examined by western blotting.
Results: Compared with cells in N group, the apoptosis of H9C2 cells induced by H/R was markedly increased [(15.79±3.92)% vs (9.74±1.14)%, P=0.028] in G group. The same was true for ROS [(489.63±21.01) U/ml vs (338.50±43.60) U/ml, P<0.001] and caspase-3 levels (1.87±0.03 vs 1.15±0.04, P<0.001), but not for Bcl-2 protein expression (1.79±0.06 vs 1.89±0.03, P=0.047). Pretreatment of cells with liraglutide (100 nmol/L) prevented the cell death induced by high glucose and H/R together with decrease of ROS and caspase-3 levels and increase of Bcl-1 expression. Moreover, treatment of cells with liraglutide also significantly increased phosphorylation of PI3K and Akt (p-PI3K/PI3K: 0.87±0.07 vs 0.59±0.09, P=0.002; p-Akt/Akt: 0.34±0.01 vs 0.08±0.01, P<0.001), eNOS[(41.29±0.56)μmpl/L vs (37.20±0.52)μmpl/L, P<0.001)and NO [(31.24±0.40)μmpl/L vs (26.66±0.53)μmpl/L, P<0.001)levels. Furthermore, addition of PI3K/Akt inhibitor wortmanin markedly inhibited the expression of p-PI3K/PI3K, p-Akt/Akt, reversed the changes of eNOS, NO, caspase-3 and Bcl-2 by liraglutide, and abolished the protective effect of liraglutide on cell apoptosis.
Conclusions: GLP-1 receptor agonist liraglutide treatment could alleviate cardiomyocytes apoptosis induced by high glucose and H/R through the activation of PI3K-Akt-eNOS-NO signaling pathway and inhibition of oxidative stress.